Antiwhistle means for exhaust system

ABSTRACT

A gas passage conduit of the type used in internal combustion engine exhaust systems has an outwardly extending recess formed in its wall adjacent a sharp-edged hole that is connected to the housing of a sound attenuating chamber.

United States Patent Robert A. Heath Jackson, Mich. T6 7,035

Aug. 26, 1970 Oct. 12, 1971 Tenneco lnc. Racine, Wis.

Inventor Appl. No. Filed Patented Assignee ANTIWHISTLE MEANS FOR EXHAUSTSYSTEM 1 Claim, 6 Drawing Figs.

U.S. Cl 181/59, 181/63 Int. Cl F0ln l/02, F0111 7/00 Field ofsearchmfi181/48,59,

Relerenees Cited UNITED STATES PATENTS 1,938,973 12/1933 Oldberg 181/632,160,332 5/1939 Huber 181/63 2,251,880 8/1941 Cary et a1. 181/632,297,046 9/1942 Boume 181/59 3,415,338 12/1968 McMillan 181/63 PrimaryExaminerRobert S. Ward, Jr. Attorney-Harness, Dickey & Pierce ABSTRACT:A gas passage conduit of the type used in internal combustion engineexhaust systems has an outwardly extending recess formed in its walladjacent a sharp-edged hole that is connected to the housing of a soundattenuating chamber.

ANTIWIIISTLE MEANS FOR EXHAUST SYSTEM BRIEF SUMMARY OF THE INVENTION Itis the purpose of this invention to eliminate the whistle that occurswhen gases in a conduit flow by a sharp-edged hole, such as the hole bywhich a tuning tube or sound attenuating chamber is connected to theconduit.

The invention accomplishes this by means of a recess formed in theotherwise smooth-walled conduit which is located adjacent the upstreamedge of the hole, the recess acting to break up the normal flow patternof gas which would result in a whistle.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation, partly brokenaway and shown schematically, of an internal combustion engine exhaustsystem embodying the invention;

FIG. 2 is a perspective view of the structure with the circle 2 of FIG.1 shown on an enlarged scale;

FIG. 3 is a side elevation of a slightly modified form of structure ascompared with that of FIG. 2;

FIG. 4 is a cross section along the line 4-4 of FIG. 3;

FIG. 5 is a view similar to FIG. 4 but showing another modification; and

FIG. 6 is also a view similar to FIG. 4 but showing still anothermodification.

DETAILED DESCRIPTION OF THE INVENTION The internal combustion engine 1has an exhaust manifold 3 which delivers gases to an exhaust system 5that includes an exhaust conduit 7 that carries gases to a muffler 9which in turn discharges them, after silencing, into a tailpipe 11. Inorder to obtain optimum sound attenuation, it is common practice to usea tuning tube or silencing chamber of some suitable design and connectit to the exhaust conduit 7 or to the tailpipe 11 at an optimumlocation. The tubular housing 13 constitutes such a silencing means andis shown in a fonn of a quarter wavelength-type tuning tube that iswelded around a hole 15 that is formed in the wall of the conduit 7. Inusage of the structure so far described, the gas flowing through conduit7 can pass by the sharp upstream edge 16 of the hole 15 and produce awhistle.

In accordance with this invention, the wall of the conduit 7 on theupstream side of the hole 15 and adjacent the upstream sharp edge 16thereof is deformed outwardly at 17 to provide a recess 19. The spaceprovided by the recess interferes with the normal flow pattern of thegas and overcomes the tendency of the gas to whistle as it passes thesharp edge on the upstream side of the hole 15.

FIG. 2 shows a single deformation 17 of some angular extent located inalignment with the housing I3 while the structure of FIG. 3 shows thesame deformation [7 along with additional circular dimples 21 that alsoextend outwardly from the tubing. FIG. 5 shows a continuous recessformed by an outwardly extending bead 23 that extends around most of thecircumference of the conduit 7; and FIG. 6 shows an annular ring 25 thatextends completely around the conduit 7. In all cases, the recessproviding deformations are located adjacent to the upstream edge of thehole 15 and when properly sized and arranged the recesses act to breakup the flow pattern and overcome the tendency to whistle.

I claim:

1. In a conduit arrangement for flowing gas such as the exhaust systemof an internal combustion engine, a substantially uniform diametertubular conduit providing a passage for gas flow in the system andhaving a sharp-edged hole in the wall thereof, a sound attenuatingdevice having housing secured to said conduit and opening through saidsharp-edged hole into the conduit, said conduit having at least oneoutwardly extending deformation formed in the wall thereof providing arecess located adjacent the upstream edge of said hold, said recessbreaking up the normal whistle-causing gas flow pattern across the sharpedge of said hole.

1. In a conduit arrangement for flowing gas such as the exhaust systemof an internal combustion engine, a substantialLy uniform diametertubular conduit providing a passage for gas flow in the system andhaving a sharp-edged hole in the wall thereof, a sound attenuatingdevice having housing secured to said conduit and opening through saidsharp-edged hole into the conduit, said conduit having at least oneoutwardly extending deformation formed in the wall thereof providing arecess located adjacent the upstream edge of said hold, said recessbreaking up the normal whistle-causing gas flow pattern across the sharpedge of said hole.